# Definist fallacy

*Also called: Persuasive definition*

- **Cluster:** Broken structure — The form itself does not carry the conclusion
- **Page:** https://fallacy.wiki/fallacy/definist/
- **In Arabic:** https://fallacy.wiki/ar/fallacy/definist.md
- **Licence:** CC BY 4.0 — https://creativecommons.org/licenses/by/4.0/

## What it is

Defining a contested term in a way that settles the dispute by wording alone.

## In the wild

> Good just means whatever I prefer, so my view is good by definition.

## How to answer it

Offer a neutral definition both sides would accept before arguing.

## Origin and naming

Charles Stevenson coined 'persuasive definition' in his 1938 paper of the same name, part of his work on the emotive meaning of ethical terms. The definist fallacy is the argumentative move built on it: smuggling a verdict into a definition so the debate is over before it starts.

## More places it shows up

- In a performance review dispute, one side defines 'productivity' as lines of code written — and suddenly one engineer is top of the team by definition.
- A lobby group defines 'family-friendly content' as content they approve of, then campaigns against everything else as anti-family.
- A founder defines 'traction' as whatever metric their startup happens to be growing, and declares the company successful.
- In a policy debate, 'reform' is defined as the speaker's own proposal, so any objection is an objection to reform.

## How to spot it

- Notice when the definition is delivered mid-argument rather than agreed on before it.
- Notice when accepting the definition means losing the debate by default — the wording is doing all the work.
- Notice when the same word keeps its emotional charge but quietly changes its content.

## Nearby

- [Circular reasoning](https://fallacy.wiki/fallacy/circular.md)
- [No true Scotsman](https://fallacy.wiki/fallacy/no-true-scotsman.md)
- [Equivocation](https://fallacy.wiki/fallacy/equivocation.md)
- [Etymological fallacy](https://fallacy.wiki/fallacy/etymological.md)

## Read more

- [Wikipedia](https://en.wikipedia.org/wiki/Persuasive_definition)
- [Wikipedia (List of fallacies)](https://en.wikipedia.org/wiki/List_of_fallacies)

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From fallacy.wiki — a bilingual field guide to 91 logical fallacies, published by phi holdings. Licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/): reuse freely with attribution to fallacy.wiki.